We live in an increasingly subscription-based economy, argues Zuora co-founder and CEO Tien Tzuo. As evidence, he points to movies, DVDs, music and even cars as things that consumers are more likely to obtain via a subscription service than through a purchase. And that's where Zuora comes in. The 7-year-old company makes the billing software for those subscription-based businesses so they don't have to manage costly and complicated in-house systems.

Zuora also helps its customers to better manage and grow the customer relationship so that they don't cancel and leave.

Tzuo is no stranger to the subscription space, having spent nine years at Salesforce.com, where he helped build its original systems and served as the company's chief marketing officer and chief strategy officer. In fact, Salesforce.com founder Marc Benioff was an investor in Zuora's first round of financing.

How did you come up with your big idea?

"I founded Zuora with the goal of empowering what I call the subscription economy, enabling businesses to make the shift towards this new but predictable recurring revenue model."-Tien Tzuo, co-founder and CEO